286
FXUS63 KFSD 160334
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1034 PM CDT Wed May 15 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms will end late this
  evening.

- Well above normal temperatures are expected Friday and Saturday
  with high confidence (>70%) on Friday.

- A more active southern stream jet is expected next week which could
  bring a better chance for increased shower and thunderstorm
  coverage.

&&

.DISCUSSION...
Issued at 212 PM CDT Wed May 15 2024

A small ribbon of instability ahead of an incoming mid and upper
level wave and surface cool front, generally along a pre frontal
trough, should allow for a few thunderstorms near and east of I-29
from about 2 pm through the evening. Surface based CAPE should be
around 1500 J/kg, but a closer inspection of the 100mb mixed layer
CAPE drops this down to 1000 J/kg or less. So while severe weather
is possible it should remain very isolated and on the lower end. The
better chances will be east of I-29 late afternoon and evening.
Otherwise more stable air will spread into the area as the upper
level wave moves by tonight. This should push the showery activity
out of the area by about midnight. One more thing to watch will be
the chance for a few funnel clouds or possibly a landspout with the
better chances in southwest MN and parts of northwest IA along the
incoming cool front where about 100-150 J/kg of 0-3km CAPE has
developed.

Thursday should be warm and dry with westerly flow. While a small
amount of instability will be possible at this time it should remain
capped. The weakest cap will be in central SD, but right now that
should still hold and even if something did develop impacts would be
pretty low. Highs generally mid and upper 70s.

While Friday and Saturday will see some small chance for showers and
thunderstorms overall each day should be mostly dry. With faster
flow aloft off to the north and west, warm conditions are expected.
We should see highs in the 80s most locations on Friday, then 70s on
Saturday as a cool front moves through.

Sunday will see the next slightly more organized threat for showers
and thunderstorms as southwest flow aloft strengthens and a mid
level wave moves through. Temperatures will be seasonally warm with
highs in the 70s.

Monday appears to be the next better chance for showers and
thunderstorms as a fairly strong southern stream low level jet
drives northward. This should bring some additional low level
moisture northward bringing a bit of an increase in instability. At
least a chance to see some 60+ surface dew points. The latest GEFS
indicating about a 30-50% chance for a half an inch or more of
rainfall Monday into Tuesday with a 20 % chance for an inch or more.

Tuesday into Wednesday will see an upper level wave move through
with a shortwave ridge building behind. This should bring a better
chance for showers and thunderstorms Tuesday vs. Wednesday. However
there may be another wave moving through Wednesday night which could
bring more chances for showers and storms. Both days should be
seasonally mild with lows in the 50s and highs in the 70s.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1032 PM CDT Wed May 15 2024

Showers and isolated thunderstorms will exit the area around
06Z. Otherwise, VFR conditions are expected through the TAF
period. Winds will be light west/northwesterly through Thursday,
then begin to turn more southwesterly on Thursday night.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...08
AVIATION...JM